In general, a vehicle brake is mainly divided into a disc brake and a drum brake. The disc brake generates a braking force based on friction created using calipers to squeeze pads against both sides of a disc that rotates together with a wheel. The drum brake obtains a braking force by squeezing brake shoes with linings (a friction material) into a drum that rotates together with a wheel.
Currently, since many technologies for achieving stability of a vehicle based on braking, e.g., anti-lock braking (ABS) and vehicle dynamic steering (VDS)/electronic stability program (ESP), have been developed, the drum brake which does not provide a sufficient braking force due to expansion when used repeatedly is not used and the disc brake is used for rear wheels as well as front wheels.
A conventional brake disc manufacturing method includes a method of manufacturing a brake disc by bond-casting cast iron and aluminum (Al) and a method of manufacturing a brake disc by using cast iron and then inserting Al foam thereinto. Even when nodular cast iron is used, upper and lower plates of the conventional cast iron disc need to have a thickness of at least 7 mm to prevent thermal deformation.